According to a large U.S. study, soda drinks, whether they be diet or regular, are linked to an increased risk of metabolic syndrome among middle-age adults.
The new research suggests that those who drink one or more soda drinks each day have a 48-percent higher risk of metabolic syndrome compared to whose who drink less and supports previous findings that soda drink consumption contributes to obesity and insulin resistance in children and hypertension in adults.
The large community based study by researchers at Boston University School of Medicine, analyzed data from subjects in the Framingham Heart Study who were in their mid-50s.
All were free of cardiovascular disease when the study began.
The Framingham Heart Study followed participants for three consecutive periods spanning 1987 to 1995 with a physical exam, food frequency questionnaires, and fasting plasma lipid, glucose, and triglyceride measurements about every four years.
Metabolic syndrome is comprised of a cluster of several cardiovascular risk factors, including high blood pressure, high cholesterol, excess fat around the abdomen and glucose intolerance, a condition in which the body can no longer process sugar in the blood that often precedes diabetes.
Until recently the link between soft-drink consumption and metabolic syndrome was purely theoretical and based primarily on the high sugar content, of the drinks.
The researchers found the results were similar whether the soda was caffeinated or decaffeinated but the reason for the similarity between findings with sugar- versus artificially-sweetened drinks was unclear.
Dr. Ramachandran S. Vasan and colleagues found that the men who drank soft drinks had 44-percent higher risk of metabolic syndrome and that drinking the soft drinks also increased the incidence of each other element of metabolic syndrome.
Past research has shown that the consumption of soft drinks is a part of the overall dietary behaviour of people and is usually accompanied by a diet high in calories and fat, and low in fiber.
But Vasan's team found that even after accounting for known risk factors such as diet, smoking and physical activity, the association between soft drink consumption and metabolic syndrome remained a significant one.
However the researchers do say that they did not find any evidence that drinking soft drinks actually caused the metabolic syndrome.
They believe a public health policy advocating a limit to the consumption of soft drinks in the community would possibly result in a lowering of the burden of metabolic risk factors in adults.
The study was supported by the National Heart, Lung, and Blood Institute and the American Diabetes Association and is published in Circulation, Journal of the American Heart Association.